Africa's wars have a terrible habit of spilling across borders. To
diplomats in Sudan, it seemed only a matter of time before the brutal
three-year-old conflict in the country's Darfur province followed suit,
posing particular risk to landlocked, unstable Chad to the west. And
indeed, this morning, residents of Chadís capital, NíDjamena, woke up to
find a small group of rebels trying to enter the city and battling
government soldiers street by street. The gunfire and shelling began at
dawn and, according to a BBC reporter in NíDjamena, lasted two hours
before the government troops overpowered the attackers, who nevertheless
promised another raid Thursday night.

The rebels, many of them defectors from Chadís army, have set
up camps across the border in lawless Darfur. Chadís President Idriss
Deby says Sudanís government in Khartoum backs the rebellion. Sudan
denies the accusation and, in turn, says Chad supports Sudanese rebel
groups in Darfur. One thing is certain: in October, hundreds of
discontented Chadian soldiers deserted their barracks and fled to
Darfur. An American military advisor in the region told TIME before
Christmas that there were at least 800 well-armed fighters along the
border, possibly more. Recent estimates put the figure in the thousands.

The rebels accuse President Deby of running a dictatorship and
say they will bring democracy to the country, which has been exploiting
its oil riches for just a few years. Successive governments in Chad have
put down regular uprisings, but this insurgency seems more serious: the
ongoing conflict in Darfur has given the rebels a secure base from which
to attack. "Chad is a sister state to Darfur," says Dr. Eltayeb Hag
Ateya, the director of the Center for Conflict Research at the
University of Khartoum. "All the presidents of Chad are either installed
by or forced out by forces that have come from Darfur."

Stopping the violence in Darfur would help. African tribal
groups there took up arms against the government in Khartoum three years
ago. The government responded by arming thousands of Arab janjaweed
militias who have wreaked havoc on African soldiers and villagers alike,
killed tens of thousands of people and forced 2 million from their
homes. The U.S. describes the campaign as genocide, but for the past two
years the world has been content to let a 7,000-strong force from the
African Union police what the United Nations describes as one of the two
worst humanitarian disasters in the world today (the other is in the
Congo). The African troops patrol an area the size of Texas, have a
limited mandate and little money. The U.N. says it may send its own
peacekeeping force to Sudan, perhaps with the help of NATO military
advisers, but troops are unlikely to arrive before the end of this year.
So far, Khartoum says it will refuse to allow them in.

And so the fighting continues  and spreads. Earlier this
year, Libya brokered a non-belligerence pact between Chad and Sudan. But
soon after the leader of the Chadian rebels, Mohammad Nour, 35, told TIME
it "is not serious" Sitting on the outskirts of a camp along the
Chad-Sudan border under the shade of a mango tree he contemplated his
next move. "Iím not going to be under these trees much longer," he said.